Alzheimer’s Database

Project title Alzheimer's database Funding Funded by a grant from the National Institute of General Medical Sciences of the National Institutes of Health About us Our goal is to expand the acquisition, processing/refinement, and immediate dissemination of a large-scale reference collection of 3D electron microscopic (EM) data, disclosing key ultrastructural details and thus advancing understanding of the hallmarks of neurodegeneration preserved within a collection of legacy biopsy brain samples (in our possession) from patients suffering from Alzheimer’s Disease (AD). We have optimized the methods for performing this work through a 1-year NIH pilot award, and we are now collecting data, which is yielding important new details, with much higher throughput than prior methods. We propose to comprehensively target areas associated with both plaques and tangles, attending to locations where existing findings suggest cell and network vulnerability and contain molecular interactions suspected by some to underlie the initiation and progression of AD. For example, in support of investigations into the progression of soma/dendritic degeneration, we will target cells operationally defined to represent a range of neuronal decline as seen in AD; determining the volume fraction of paired helical filaments (PHF) in the cytoplasm as a practical staging measure and linking this to the characterization of quantitative changes in microstructure of major subcellular constituents (e.g., nuclei, nuclear pores, Golgi, endoplasmic reticulum (both RER and SER), microtubules, mitochondria, etc.). Likewise, we will analyze the progression of axonal degeneration in and near plaques as data obtained suggests that axons may become dystrophic before their parent cell bodies and their dendrites degenerate. To assess this, we will reconstruct axons which are in close proximity to amyloid fibrils of perivascular plaques and trace these proximally (away from the amyloid). The remarkable collection of legacy biopsy brain samples fueling this effort was originally collected, characterized and archived by neuropathologists R.D. Terry and N. Gonatas1 (at A. Einstein in the late 1960’s), with later samples taken as part of a cerebrospinal fluid (CSF) drug infusion study involving S. Mirra (at Emory in the 1980’s).2 These samples were screened and preliminarily reported on by Ellisman, Masliah, Terry and Mirra3 and manifest excellent preservation of ultrastructure, showing PHF and amyloid accumulations as well as modifications to subcellular organelles and cytoskeletons of the cell bodies, axonal and dendritic processes. Our original work employed early and tedious versions of serial section transmission EM, (ssEM) resulting in ~10 small 3D data volumes. We will now exploit recent advances in high throughput, automated 3D EM to fully reconstruct 100s of brain cells with and without PHF, tracking axons (and mapping glia and synapses) through much greater brain volumes than was feasible previously.

The Team

Mark Ellisman, Ph.D.

Principal Investigator